FIG. 1 is a schematic view illustrating a conventional slim-type optical disc drive. As shown in FIG. 1, the slim-type optical disc drive comprises a tray 110, a casing 112, and two sliding rails 140, 142. After the tray 110 is pushed into the casing 112 of the optical disc drive, the tray 110 is fixed within the casing 112 by a tray locking unit (not shown). Under this circumstance, the tray 110 is in a tray-in status. Whereas, after an eject button 114 on the tray 110 is pressed by the user, the tray locking unit will release the tray 110, so that the tray 110 will be ejected out of the optical disc drive. Under this circumstance, the tray 110 is in a tray-out status. In other words, if the tray 110 is not stored within the casing 112 and the tray 110 is in the tray-out status, the tray 110 may be further pulled out along the rails 140 and 142 by the user. After the tray 110 is pulled out, the optical disc 102 loaded on the tray 110 may be replaced with a new one or and then the tray 110 is pushed into the casing 112 (i.e. in the tray-in status).
Moreover, a daughter board (not shown) is fixed within the tray 110. A main board 160 is fixed on the casing 112. The main board 160 comprises a main control circuit 162. The main board 160 and the daughter board are in communication with each other to transmit signals through a flexible cable 150. In other words, during the process of moving the tray 110, the daughter board is still in communication with the main board 160.
Please refer to FIG. 1 again. The tray 110 comprises a spindle motor 120. The spindle motor 120 is fixed on the daughter board (not shown). The optical disc 102 may be placed on the spindle motor 120. The tray 110 further comprises an optical pickup head (OPU) 130. The optical pickup head 130 further comprises an actuator control unit (not shown). The optical pickup head 130 may emit a laser beam. The focusing action, track-crossing action and track-following action of the laser beam are controlled by the actuator control unit in order to access data recorded on the tracks of the optical disc 102.
Moreover, the optical pickup head 130 may be moved on the tray 110 along the radial direction of the optical disc 102 in order to access the data recorded on any track of the optical disc 102. If the optical pickup head 130 is located close to the spindle motor 120, it means that the optical pickup head 130 is close to the inner track of the optical disc 102.
In other words, after the optical disc 102 is fixed on the spindle motor 120 and the tray 110 is pushed into the casing 112 to be in the tray-in status, the spindle motor 120 may start driving rotation of the optical disc 102. Consequently, the data of the optical disc 102 can be accessed by the optical pickup head 130.
FIG. 2 is a flowchart illustrating a method for stopping the spindle motor of the conventional optical disc drive. Once the eject button 114 of the optical disc drive is pressed, it means that the optical pickup head is about to be disabled. Meanwhile, the main control circuit 162 will sequentially perform the following steps. Firstly, the optical pickup head 130 is moved to a position corresponding to an inner track of the optical disc 102 (Step S202). Then, the actuator control unit is disabled (Step S204). Then, the laser source is turned off (Step S206). Then, the spindle motor 120 is controlled to be braked until the spindle motor 120 is stopped (Step S208). After the main control circuit 162 confirms that the spindle motor 120 is completely stopped (i.e. the rotating speed is zero), the main control circuit 162 controls the tray locking unit (not shown) to release the tray 110. Under this circumstance, the tray 110 is ejected out of the optical disc drive, and thus the tray 110 is in the tray-out status.
Basically, the above steps should be sequentially done. In a case that the tray 110 is in the tray-in status, once the eject button 114 is pressed by the user, the optical pickup head 130 is controlled to be moved to the position corresponding to the inner track of the optical disc 102 from the time spot t0 to the time spot t1 (Step S202). From the time spot t1 to the time spot t2, the actuator control unit is disabled (Step S204). From the time spot t2 to the time spot t3, the laser source is turned off (Step S206). From the time spot t3 to the time spot t4, the spindle motor 120 is controlled to be braked until the spindle motor 120 is stopped (Step S208). After the time spot t4, the main control circuit 162 confirms that the spindle motor 120 is completely stopped, and thus the main control circuit 162 controls the tray locking unit (not shown) to release the tray 110. Under this circumstance, the tray 110 is ejected out of the optical disc drive, and thus the tray 110 is in the tray-out status. From the above discussions, when the tray 110 is in the tray-out status, the optical disc drive should assure that the rotation of the optical disc 102 is completely stopped. That is, the spindle motor 120 is completely stopped. Since the optical disc 102 is no longer rotated, when the tray 110 is ejected out of the casing 112, the user will not be hurt by the optical disc 102.
In other words, the tray 110 is in the tray-in status from the time spot t0 to the time spot t4. After the time spot t4, the tray 110 is in the tray-out status. Consequently, after the eject button 114 of the optical disc drive is pressed by the user, it takes a time period (i.e. t0˜t4) to wait for the tray 110 to be ejected out of the casing 112.
However, since the spindle motor of the conventional optical disc drive usually contains rare earth material, the cost of the spindle motor is very high. For reducing the fabricating cost of the optical disc drive, a spindle motor with no rare earth material is provided. For example, the spindle motor with no rare earth material is a ferrite motor.
As known, the spindle motor with no rare earth material fails to complete the braking action in a very short time. If the method for stopping the spindle motor as described in FIG. 2 is applied to this non-rare earth spindle motor, the whole cycle of ejecting the tray is very long. Under this circumstance, the optical disc drive with the non-rare earth spindle motor fails to pass the factory test, or the optical disc drive with the non-rare earth spindle motor is not user-friendly because of the long-term braking action.